Supplementary feeding of wild birds is one of the most widespread forms of human-wildlife interaction. Done well it benefits birds; done poorly it can cause disease and dependency.
Wild bird feeding at its best supplements natural food availability during scarcity and provides welfare benefit to individual birds and population-level support for declining species. At its worst, poorly maintained feeding stations concentrate disease, provide nutritional deficiencies and create dependency in populations that lose foraging range as food is always available in one location. The evidence on population effects is mixed: some species have clearly benefited from supplementary feeding; others face disease risks that outweigh benefits. Best practice focuses on feeder hygiene, species-appropriate food, feeder positioning to reduce cat predation risk and consistent provisioning during breeding season when energy demands are highest.